Method and apparatus for the treatment of hydrocarbon oils



5, 1963 1. E. PUDDINGTON ETAL 3,109,805

METHOD AND APPARATUS FOR THE TREATMENT OF HYDROCARBON OILS Filed June 30, 1958 United States Patent METHQD AND APPARATUS FOR THE TREAT- MENT 0F HYDROCARBQN OILS Ira Edwin Puddington, 2324 Alta Vista Drive, and

Aurelio F. Sirianni, 1630 Abbey Road, both of Ottawa, Ontario, Canada Filed June 3%, 1958, Ser. No. 745,438

12 Claims. (Cl. 208-179) The present invention relates to a process and apparatus for the continual treatment of hydrocarbon oils, such as, for example, lubricating oils, transformer oils, fuel oils and heat transfer oils, in order to reduce or prevent deterioration of such oils during use.

Hydrocarbon oils of the type mentioned tend continually to deteriorate and this results in discoloration and sludge formation, as well as in the formation of acid reacting products. Such deterioration is evidently caused by oxidation reactions and also by thermal decomposition. In the case of lubricating oils, the weight of the research into the causes of deterioration of these oils indicates that the main cause is oxidation and that thermal decomposition, at least at normal engine lubricating temperatures, is a comparatively minor contributory factor. However, the results of the deterioration of hydrocarbon oils are well known, especially by motorists who find it necessary, as a consequence, to eifeot periodic oil changes with the attendant extra trouble and expense. Also, research has indicated that engine deterioration and wear are traceable to the deterioration of the lubricating oils during use.

It is the object of the present invention to provide for a simple and inexpensive continual treatment for hydrocarbon oils to reduce or remove their tendency to deteriorate during storage or use. As indicated, the tendency of hydrocarbon oils to deteriorate is a continual one and consequently a continuous puocess is required to combat it. This is an important factor to be borne in mind since it is radically different in this respect from other types of oil treatment, such as refining. In the latter instance, the oil is given some treatment to effect the desired improvement and thereafter the oil is considered as so improved and in need Olf no repetition of the treatment, For example, oils are treated to remove wax and asphalt but, once these substances are removed, no repetition of treatment is necessary as there will be no further formation of addition of such substances to warrant further treatment. In such cases, the treatment will usually consist of a continuous process in which the untreated oil is passed through the treating apparatus in a continuous stream and then removed to be employed as required.

In contradistinction, according to the present invention, a continual treatment of substantially the same batch of oil is effected so that its tendency to deteriorate is continually combatt-ed in order to prevent discoloration and sludge formation irom taking place, as Well as to prevent such oil from assuming an acid reaction. Thus, the present invention provides a method for the continual treatment of a hydrocarbon oil to combat its continual tendency to deterioration which comprises continually recycling said oil through a treating zone in contact with a fixed sodium-lead alloy or a fixed sodium-lead-tin alloy,

said alloys containing sufiicient sodium that they are readily corrodable under conditions of use.

Thus, according to the invention it was found that when hydrocarbon oils of the type mentioned are maintained in continual contact with even only a relatively small element, the essential components of which are certain solid sodium-lead alloys or certain sodium-lead-tin alloys, preferably with movement of the oil over such element, such as by recycling the oil through a treating zone containing the element so as to ensure thorough contact of both the sodium-lead alloy or the sodium lead-tin alloy surfaces with the oil, the normal tendency of such oils to deteriorate is reduced to a very substantial degree.

While the most efficient materials for retarding acid deterioration of hydrocarbon oils are the alkali metals, such as sodium, potassium and lithium, sodium is, because of its relatively lower cost, the only one practically coming into consideration. Sodium in itself, however, has a number of drawbacks in that it is a soft low density metal which oxidizes very easily in air and melts at 97 C. Furthermore, it reacts with water, sometimes with violence, and must be handled with care in the presence of moisture. Therefore, while sodium in itself is efiicient in retarding the deterioration of hydrocarbon oil-s, it is not too safe to use under practical conditions, such as, for example, in a crankcase of an internal combustion engine, where the sodium may be in direct contact with heat and moisture. However, according to the invention it was found that these difficulties can effectively be overcome by employing sodium in the form of its indicated alloys with lead and tin or with lead alone. The metal to be alloyed with the sodium according to the invention, for example, can be lead or lead-tin alloys containing up to about 95% tin.

The minimum amount of sodium which should be present in the alloy to render that alloy corrodable under conditions of use has been found to be about 20-25 atom percent. A sodium alloy which is corrodable under conditions of use may be defined as one which contains at least the minimum atom percent amount of sodium required to give the rate of corrosion of the alloy necessary to maintain the oil substantially neutral. It has been found in most cases that the oil is, in fact, held substantially Within the same pH as the fresh, unheated oil. At concentrations of sodium below about 20-25 atom percent it has been found that the alloy is not sutficiently corrodable to liberate the sodium atoms at a suflicient rate to prevent the rformation of acidic products in the oil.

It is not theoretically necessary to place an upper limit on the amount of sodium in the sodium-lead] alloys or sodium-lead-tin alloys. However, it is desirable for practical reasons to impose restrictions on the maximum amount of sodium. An excessive amount of sodium renders the alloys too fragile and pyrophoric or too active in the presence of water. It has been found that a practical maximum of sodium in the sodium-lead-alloys should be about 70 atom percent, while for the sodium-lead-tin alloys the practical maximum amount of sodium is about atom percent.

The invention is particularly applicable to oils While in use and therefore particularly subject to deterioration.

An application of the invention which has been found particularly effective involves oil which is circulating in the oil lubricating circuit of an internal combustion engine. In such case, the continual treatment according to the invention can, for example, be carried out by positioning the sodium-lead alloy or the sodium-lead-tin alloy containing element in the circuit so that the circulating oil will continually contact the sodium-lead alloy or the sodium-lead-t-in alloy surfaces. Preferably, the element according to the invention is placed in the oil circuit in such a manner that it can readily be changed. For example, the element can be secured to a supporting member which is capable of being in or adjacent to the oil circuit so that the sodium-lead allow or the sodiumlead-tin alloy surfaces will contact the oil in the circuit. It has, for example, been found particularly expedient to secure the sodium-lead alloy or the sodium-lead-tin alloy to the inner end of a crankcase drain plug. Also, the element according to the invention may be inccorporated in a filter inserted in the oil circuit.

It has been found highly satisfactory to use the sodiumlead-tin alloy or the-sodium-lead alloy in massive form in the treating element according to the invention.

However, it is also possible to use in particulate form either or both of the solid sodium-lead alloy or sodiumlea-datin alloy providing adequate means are provided to prevent such particles from 'being entrained by the oil leaving the treating zone while at the same time maintaining adequate contact between the particles and the circulating oil. It was found, however, that in use an cecasional small particle may be so entrained but this can be tolerated.

It is, of course, also possible to apply the treatment to the oil while in storage. In that event, oil may be continually pumped or otherwise recycled from the storage tank to a small treating chamber containing the treating element and then back to the tank. More advantageously, however, the treatment may take place in the tank itself. A number of the treating elements may be suspended in the oil to form a number of treating zones, and the oil may be recycled through such zones either by natural convection currents, if these are suflicient, or by positive means for producing recycling currents. In that connection, it is to be noted that the term recycling is used herein broadly to include both positive and natural recycling. The means of recycling is clearly immateral provided that recycling is actually achieved.

The action of the sodium in the element according to the invention in combatting deterioration is not entirely understood. Oxygen itself is believed to have little harmful effect. Oxidation of hydrocarbon lubricating oils is thought to be caused by the formation of hydroperoxides of hydrocarbons in the oil followed by a chain reaction involving free radicals. In line with this it has been found that compounds which produce free radicals, such as benzoyl peroxide and ditertiary butyl peroxide, in-

crease the rate of deterioration of the oils markedly. It

is believed that the sodium in the allows according to the invention serves either to stabilize the said hydroperoxide compounds or to decompose such compounds.

One of the sodium alloys useful in the treating element of the present invention is a sodium-lead-tin alloy. It can, for example, contain 20-65 atom percent of metallic sodium. The composition of the lead-tin component in the alloy, varying from 5 to 95% by weight lead and the remainder tin has been found to be successful. A 50%.-50% by weight lead-tin solder has been particularly elfective in the production of the sodium-lea'd-tin alloy employed according to the invention.

Another of the sodium alloys useful in the treating element of the present invention is a sodium-lead alloy. Such alloy may conveniently contain from about 2025 atom percent up to about 70 atom percent of sodium,

preferably from about 20 to about 70 atom percent sodium.

In drawing which illustrate embodiments of the invention,

FIG. 1 is an elevation of a plug adapted to be aflixed threaded extension 2 which can be of steel.

bodiment of a plug according to the invention is composed of a threaded head 1 which carries a narrower Element 3, composed of an alloy of sodium which may be a sodiumlead alloy or the sodium-lead-tin alloy, is carried by threaded extension 2. which serves to hold such element. As shown in FIG. 2, when such plug is used as a crankcase drain plug, it serves to close the drain opening in crankcase 5 of an internal combustion engine and in such position the inner end carrying element 3 is maintained in continuous contact with the lubricating oil 6 circulating through the crankcase.

Referring now to the embodiment shown in FIG. 3, it is seen that the plug consists of a threaded head 11 and an oil-contacting portion designate-d generally by 13. In the embodiment shown in FIG. 3, parts 11 and 13 are interconnected by an interconnecting element 1 2', having a swivel-type ball joint connection (not shown in detail) to 11. The purpose of such ball joint is to permit adjustment of thepos'ition of 13. In the modification shown in FIG. 4, 11 and 13 are interconnected by 12, an integral threaded extension of 1 1. The oil-contacting portion of the drain plug, designated generally by 13, consists of a wire basket 14, equipped with a wire mesh end closure 15 and a solid bottom designated as 16 in FIG. 4 and as 16' in FIG. 3 which may be of steel. The bottom 16 or 16' is internally tapped to receive member 12 or 12'.

The treating elements according to the invention should be constituted so that practically sized elements will remain effective for over a year when placed in the oil circuit of an internal combustion automobile engine. Their use not only effectively reduces sludging and discoloration of lubricating oil or other hydrocarbon oils subject to deterioration during use or storage, but also effectively prevents such oils from acquiring an acid reaction. The latter is most important in lubricating oils for internal combustion engines: use of the elements according to the invention so as to maintain the sodiumlead alloy or the sodium-leadtin alloy continuously in contact with the lubricating oil will tend to reduce engine wear, thus extending the time before the engine will tend to start using oil. Furthermore its use tends to reduce the frequency of oil changes, and may even obviate the necessity for such oil changes.

The treating elements according to the invention have also been found useful when maintained in contact with hydrocarbon transformer oils, hydrocarbon fuel oils and hydrocarbon heat transfer oils.

The effectiveness of the sodium-lead alloy and of the sodium-lead-tin alloy according to the invention is illustrated in the following examples which give the results of laboratory tests carried out under conditions where the oils involved are normally subject to rapid deterioration.

Various sodium-containing alloys were prepared con taining from 6 ltO 7O atom percent sodium (1 to 20% by weight). In general, the tests were carried out in the following manner, except when specified otherwise:

The sodium-containing alloy to be tested was added to 50 grams of refined lubricating oils contained in clean cc. glass beakers. The samples were heated in the open beakers for various periods of time and to various temperatures. Since degradation of the oils results in the formation of acidic materials, assessment of the condition of the various oils was made by pH measurements. Such pH determinations were carried out by dissolving 2 grams of the oil in 10 cc. of neutral 50:50 benzene:isopropyl alcohol solution containing 0.5% of Water, and determining the pH electrometrically. The results are more conveniently evaluated by observing the diflerence in pH (ApH) between the treated oil and the heated but untreated oil. Thus ApH=pH (treated oil) pH (untreated oil) after both have received similar heat treatments.

In those tests where copper and iron were also introduced into the oils in order that they also be in contact with the metals which, for example, may be present in lubricating systems or oil containers, the copper was in the form of a 50 mil copper wire about 3 to 3.5 inches long and the iron was in the form of a 45 mil iron wire about 3 to 5.5 inches long. The condition of the various oils Was assessed by pH measurements as hereinabove described.

EXAMPLE 1 Solid pieces of sodium solder alloys having .a geometric area of 0.6 cm. were each added to 50 grams of a refined SAE #20 lubricating oil (having an original pH of 7.72) and then heating such oil in an open beaker up to 96 hours at 157 C. The solder component of such sodium solder alloy was a 50-50 percent by Weight lead-tin solder. In addition comparative tests were made with magnesium-aluminum alloy, Zinc, lead, solder (50- 50 Pb-Sn), sodium-calcium and sodium-magnesium alloys. The results are given in the following table:

Table I LUBRIOA'IING OIL NU SAE #20, HEATED UP TO 96 HOURS AT 157 C.

ApH Sample addition After 24 hrs. After 96 hrs.

Heated untreated oil (blank) (Actual pH 0 (Actual pH 4.92) 4.01) -0. 04 -0.03 sludgcd -0.30 0.10 sludged 0.32 -0.10 sludged 7% Magnesium-aluminum al1oy. 0.30 -0.09 sludged 2% Sodium-calcium alloy 0 0.20 10% Sodium-calcium alloy 0.03 0.27 2% Sodium-magnesium alloy 0.1 0.23

Sodium-solder alloys containing:

ApH Percent Na By Weight Na atoms,

percent After 24 hrs. After 90 hrs.

It will be seen that for a sodium solder alloy to be efiective as an inhibitor for the degradation of the lubricating oil, it is necessary that the alloy contains above about 20-25 atom percent of sodium. Those containing less sodium are believed insufiiciently corrodable to effect inhibition when the oil is under oxidative conditions. It will also be seen that the 2-10% by weight sodiumcalcium alloys, 2% sodium-magnesium alloy and Zinc were virtually useless as inhibitors.

EXAMPLE 2 Solid pieces of sodium-lead alloys having a geometric area of 0.6 cm. were each added to 50 grams of a refined Table II LUBRICATING OIL NU sit; i;%O7, %EATED UP T0 96 HOURS ApH Sample addition After 24 hrs. After 96 hrs.

Heated untreated oil (blank) 0 (Actual pH 4.00) sludged 0 (Actual pH Sodium-lead alloys containing:

ApH Percent Na By Weight Na atoms,

percent After 24 hrs. After 90 hrs.

It will again be seen that the effectiveness of the sodium-lead alloys begins at about 2025 atom percent of sodium, although not as clearly defined as in the case of the sodium solder alloys.

EXAMPLE 3 Table III DE. SAE #30 LUBRICATINGlgI LOHEATED FOR 30 HOURS AT Sample addition ApH Heated untreated oil (blank) 0 (Actual pH 2.81 7% Magnesium-aluminum alloy 0.05 2% Na-calcium alloy 0 10% Na-calcium alloy 0 Zinc 0.08 Lead 0.09 Solder 0.03

Sodium-solder alloys:

Percent Na By Weight Na atoms, ApH

percent Table III-Continued EXAMPLE 4 Solid pieces of sodium-solder (solder=50-5O lead-tin) and sodium lead alloys having a surface area of 1.8 cm.

were immersed into 50 grams of an SAE #30 lubricating Table IV LUBRICATING OIL NU SAE15#739,(1J IEATED FOR 65 HOURS AT Sample ApH Untreated (heated) oil (Actual pH 4.0) sludged.

Sodium solder alloys:

Percent Na by Weight Na atoms, ApH

percent 1. 6. 2 0.20 sludged 2. 11. 8 0.31 sludged 3. 16. 9 0.30 sludged 4 21.5 3. 71 5. 25. 7 3. 28 7- 33.1 3. 59 10 42.1 3.10 1 R 53. 6 4. 90 62.1 4.15

Sodium-lead alloys:

Sample ApH Percent Na By Weight Na atoms,

percent EXAMPLE 5 Solid pieces of sodium-solder (solder=5050 lead-tin) and sodium-lead alloys having geometric areas of 3.1 0111. were immersed in 50 grams of a refined SAE #20 lubricating oil (having an original pH of 7.92). which also contained 3 inches of 50 mil copper wire as an impurity. In addition, comparative tests were made with a similar area of zinc, Mg, solder (SO-5O Pb-Sn), lead, 2% Na-C-a alloy, 10% Na-Ca alloy. The samples were heated for 44 hours at 145-150 C. in open glass beakers.

The results of such test are given in the following table:

Table V LUBRIOATING OIL SF SAE #20, HEATED FOR 44 HOURS Al Sample addition ApH Heated untreated oil (blank) Oil-I-Cu. Zine+Ou. Mg-i-Cu. So1der+Cu Lead+Cu Atomic Na 3.4% (2% Na-Ca) Atomic Na 16.2% (10% Na-Ca) 0 (Actual pH Sodium-lead alloy containing:

Sample addition ApH Percent Na by weight Na atoms,

percent 1. 8. 34+Ou 0.41 2 15. 5 +Cu 0. 60 3. 21.7 +Ou 3. 60 4- 27.3 +011 4.48 5. 32.1 +Cu 4.20 7. 40.5 +Cu 4.64 10. 50.1 +Cu 4. 91 15. 61.9 +Cu 5.51 20 69.3 +011 5. 79

Sodium-solder alloy containing:

Sample addition ApH Percent Na by weight Na atoms,

percent 2.. 11. 8+Cu 0.82 3. 16. Q-l-Cu 0.79 4.. 21. 5+Cu 3. 20 5 25. 7+ Cu 4. s1 7. 33.1+Cu 4.18 10. 42. 1+Cu 4. 47 15. 53. 6+Cu 4. 95 20. 62.1+Cu 5. 70

It will be seen that despite the presence of copper metal which is a well known oxidation catalyst for lubricating oil, the sodium alloys above a certain minimum concentration of sodium markedly decrease the formation of acidic constituents in the oil. Below this minimum the effect of the sodium is only very nominal.

EXAMPLE 6 Solid pieces of sodium-solder alloy (solder:5050 lead-tin) having freshly cut surfaces of an area of 5 cm; were immersed in 50 grams of a SAE #30 refined lubricating oil (having an original pH of 8.18) in open beakers. The open beakers containing the oil were heated first for 65 hours at 157 C. and the resulting pH measured. After the pH measurements were taken, the alloy was removed from the oil and placed in 50 g. of fresh oil and heated therein for 28 hours at 157 C. and the resulting pH again measured. Thereafter, the alloy was again removed and placed in 50 g. of fresh oil and heated therein for a further 65 hours at 157 C. and the resulting pH again measured so that the alloy was subjected to three cycles.

The results of this test are summarized in the following table:

Table VI ApH Sample addition 1st 2nd 3rd (65 hrs.) (28 hrs.) (65 hrs.)

Heated untreated oil (Actual 0 (Actual 0 (Actual pH 4.00) pH 4.70) pH 4.09) sludged sludged sludged Sodium-Solder alloys Percent Na by Na atoms,

Weight Percent EXAMPLE 7 Solid pieces of sodium-solder alloy (prepared by melting together (42.1 atom percent) of sodium with a 5050 Pb-Sn solder) weighing about 1-1.5 grams were each added to 50 grams of SAE #20 naphthenic lubricating oil containing no additives (having an original pH of 7.48). The samples were heated in 100 cc. open glass beakers for 70 hours at 145 C. and the pH at the completion of the run measured and compared with those of blank samples of the oil heated under the same conditions. The blank heated samples of the oil had a pH of 3.70 and sludged, whereas the samples of the oil containing the sodium-solder alloy had a pH of 8.98 and contained no sludge.

EXAMPLE 8 Similarly to Example 7, the effect of the addition of the sodium-solder alloy described therein was tested with a lightly refined hydrocarbon oil, sometimes used in heat transfer work, which originally exhibited a pH of 7.03. In this test the heating was for 68 hours at 125 C. At the end of the test the blank heated samples had a pH of 4.51, whereas the samples containing the sodium-solder alloy had a pH of 6.96.

EXAMPLE 9 Similarly to Example 7, the efiiect of the addition of the sodium-solder alloy described therein was tested with a highly refined paraffinic oil, SAE #20, having an original pH of 8.50. In this test the heating was for 46 hours at 160 C. At the end of the test the blank heated samples had a pH of 3.69, Whereas those containing the sodium-solder alloy had a pH of 9.13.

EXAMPLE 10 Similarly to Example 7, the efiect of the sodium-solder alloy was tested with a lubricating oil for API services MS DG having a viscosity of SAE 10 and having an original pH of 7.40. In this test the heating was for 137 hours at 160 C. At the end of the test the blank heated samples had a pH of 4.39, whereas those containing the sodium-solder alloy had a pH of 7.51.

10 EXAMPLE 11 Similarly to Example 7, the effect of the sodium-solder alloy was tested with a non-additive lubricating oil having an original pH of 9.50. In this test the samples were heated respectively for 40 and 137 hours at 160 C. After the 40 hours heating, the blank samples had a pH of 7.68, whereas those containing the sodium-solder alloy had a pH of 8.77. After the 137 hours heating, the blank samples had a pH of 4.92, whereas those containing the sodium-solder alloy had a pH of 9.21.

EXAMPLE 12 Similarly to Example 7, the eifect of the sodium-solder alloy was tested with a highly refined paraifinic SAE #20 lubricating oil exhibiting an original pH of 8.91. In this test the heating was for 46 hours at 160 C. Upon completion of the test the blank oil samples had a pH of 2.19, whereas those containing the sodium-solder alloy had a pH of 8.01.

EXAMPLE 13 Similarly to Example 7, the eifect of the sodium-solder alloy was tested with a commercial parafi'inic Pennsylvania type lubricating oil SAE #20 having an original 101 1 of 8.14. In this test, however, the sodium-solder alloy was added to 50 grams of the oil also containing 3.5 inches of 50 mil copper wire and 5.5 inches of 45 mil iron wire. In this test the heating was for 133 hours at 127 C. Upon completion of the test the heated blank samples (containing the Fe+Cu, but no Na-Pb-Sn alloy) had a pH of 4.10, whereas those containing the sodiumsolder alloy had a pH of 8.87.

EXAMPLE 14 Similarly to Example 13, the eiiect of the addition of the sodium-solder alloy was tested with a naphthenic oil used for making lubricating greases having an original pH of 9.16. In this case also the samples had copper and iron added as in Example 13. In this test the heating was for 133 hours at 130 C. Upon completion of the test the blank heated samples (containing Cu-l-Fe, but no Na-Pb-Sn alloy) had a pH of 4.89, whereas those containing the sodium-solder alloy had a pH of 7.74.

EXAMPLE 15 Similarly to Example 13, the eiiect of the addition of the sodium-solder alloy was tested with a heavy duty motor oil for API services MM, MS and DG, SAE #20 having an original pH of 8.49. In this case also the samples had copper and iron added as in Example 13. In this test the heating was for 88 hours at 127 C. Upon completion of the test the blank heated samples (containing Cu+Fe, but no Na-Pb-Sn alloy) had a pi-l of 6.59, whereas those containing the sodium-solder alloy had a pH of 7.61.

The following example illustrates a field test with a Ford car:

EXAMPLE 16 A cylindrical stick, measuring 3 inches in length and inch in diameter was prepared of an alloy containing by weight 10% sodium and solder (10% by Weight of Na=42.1 atom percent), the solder comprising equal parts by weight of lead and tin. This stick was placed in a cylindrical container about 6 inches in length and inch in diameter, and such container was inserted into the oil circuit of the car just upstream of the filter.

This was done in the car when the mileage stood at 10,695. The car was then driven for 11,905 further miles without an oil change and merely adding oil as necessary to replace losses. A sample of the oil was then taken and it was noted that there was very little sludge formation and that the color of the oil was lighter than the customary color of oil used with that car for just 1000 miles Without any treating metal of the present in- 1 l vention. The oil even after 11,905 miles had substantially the same lubricating properties as when new.

The car was driven then for 1,988 further miles with the same oil, again adding oil as necessary to replace losses. The oil was then checked again and the sludge and color was substantially the same as at the previous check after driving 11,905 miles. The oil still had excellent lubricating qualities, and it was still by no means necessary to effect an oil change. This was after having driven 19,893 miles using the treatment of the present invention, which is quite remarkable having regard to the normal recommendation to change the oil about every 1500miles.

This application is a continuation-in-part of application Serial No. 598,855, filed July 19, 1956, now Patent No. 2,852,454, and a continuation-in-part of application Serial No. 574,356, filed March 21, 1956, now abandoned, which is a continuation-in-part of application Serial No. 288,754, filed May 19, 1952 (now abandoned).

We claim:

1. A method for the continual treatment of a hydrocarbon oil exposed to conditions tending to cause oxidation of such oil to combat its continuous tendency to deterioration under such conditions which comprises continually recycling said oil through a treating zone in contact with a fixed solid alloy of sodium with an alloying component selected from the group consisting of lead and lead-tin alloys containing up to 95% of tin, the quantity of sodium in said alloy being at least 20 atom percent.

2. A method for the continual treatment of a hydrocarbon oil exposed to conditions tending to cause oxidation of such oil to combat its continuous tendency to deterioration under such conditions which comprises continually recycling said oil through a treating zone in contact with a fixed solid alloy of sodium and lead containing 20 to 70 atom percent of sodium.

3. A method :for the continual treatment of a hydrocarbon oil exposed to conditions tending to cause oxidation of such oil to combat its continuous tendency to deterioration under such conditions which comprises continually recycling said oil through a treating zone in contact with a fixed solid alloy of sodium with a lead-tin alloy containing up to 95% of tin, said sodium-lead-tin alloy containing 2-0 to 65 atom percent of sodium.

4. A method for the continual treatment of a hydrocarbon lubricating oil circulating in a lubricating oil circuit of an internal combustion engine to combat the continual tendency of said oil to deteriorate which comprises, during the operation of said engine, continually passing the oil in said circuit through a treating zone in contact with a fixed solid alloy of sodium with an alloying component selected from the group consisting of lead and lead-tin alloys containing up to 95% of tin, the quantity of sodium in said alloy being at least 20 atom percent.

5. A method for the continual treatment of a hydrocarbon lubricating oil circulating in a lubricating oil circuit of an internal combustion engine to combat the continual tendency of said oil to deteriorate which comprises, during the operation of said engine, continually passing the oil in said circuit through a treating zone in 12 contact with a fixed solid alloy of sodium and lead containing 20-70 atom percent of sodium.

6. A method for the continual treatment of a hydrocarbon lubricating oil circulating in a lubricating oil circuit of an internal combustion engine to combat the continual tendency oi said oil to deteriorate which comprises, during the operation of said engine, continually passing the oil in said circuit through a treating zone in contact with a fixed solid alloy of sodium with a lead-tin ai'loy containing up to 95% of tin, said sodium-lead-tin alloy containing 20 to atom percent of sodium.

7. An element for the treatment of hydrocarbon oil exposed to conditions tending to cause oxidation of such oil to lessen its tendency to deterioration under such conditions comprising a supporting member carrying an exposed solid alloy of sodium with an alloying component selected from the group consisting of lead and lead-tin alloys containing up to 95% of tin, the quantity of sodium in said alloy being at least 20 atom percent, said supporting member being adapted to be positioned in an oil container with said sodium alloy in contact with theoil.

8. An element for the treatment of hydrocarbon oil exposed to conditions tending to cause oxidation of such oil to lessen its tendency to deterioration under such conditions comprising a supporting member carrying an exposed solid alloy of sodium and lead containing 20 to atom percent of sodium, said supporting member being adapted to be positioned in an oil container with said sodium alloy in contact with the oil.

9. An element for the treatment of hydrocarbon oil exposed to conditions tending to cause oxidation of such oil to lessen its tendency to deterioration under such conditions comprising a supporting member carrying an exposed solid alloy of sodium with a lead-tin alloy containing up to of tin, said so-dium-lead-tin alloy containing 20 to 65 atom percent of sodium, said supporting member being adapted to be positioned in an oil container with said sodium alloy in contact with the oil.

10. A crankcase drain plug carrying on its inner end an exposed solid alloy of sodium with an alloying component selected from the group consisting of lead and leadtin alloys containing up to 95 of tin, the quantity of sodium in said alloy being at least 20 atom percent.

11. A crankcase drain plug carrying on its inner end an exposed solid alloy of sodium and lead containing 20 to 70 atoms percent of sodium.

12. A crankcase drain plug carrying on its inner end an exposed solid alloy of sodium with a lead-tin alloy containing up to 95 of tin, said sodium-lead-tin alloy containing 20- to 65 atom percent of sodium.

References Cited in the file of this patent V UNITED STATES PATENTS 856,361 Neiburg June 11, 1907 1,752,050 Young Mar. 25, 1930 1,801,412 Carlisle Apr. 21, 1931 1,862,003 Carlisle et a1. June 7, 1932 2,852,454 Puddington et al Sept. 16, 1958 

1. A METHOD FOR THE CONTINUAL TREATMENT OF A HYDROCARBON OIL EXPOSED TO CONDITIONS TENDING TO CAUSE OXIDATION OF SUCH OIL TO COMBAT ITS CONTINUOUS TENDENCY TO DETERIORATION UNDER SUCH CONDITIONS WHICH COMPRISES CONTINUALLY RECYCLING SAID OIL THROUGH A TREATING ZONE IN CONTACT WITH A FIXED SOLID ALLOY OF SODIUM WITH AN ALLOYING COMPONENT SELECTED FROM THE GROUP CONSISTING OF LEAD AND LEAD-TIN ALLOYS CONTAINING UP TO 95% OF TIN, THE QUANTITY OF SODIUM IN SAID ALLOY BEING AT LEAST 20 ATOM PERCENT. 